Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 56c94dc5 authored by Taeung Song's avatar Taeung Song Committed by Arnaldo Carvalho de Melo
Browse files

perf config: Document variables for 'call-graph' section in man page 



Explain 'call-graph' section and its variables:

  'record-mode', 'dump-size', 'print-type', 'order', 'sort-key',
  'threshold' and 'print-limit'.

Signed-off-by: default avatarTaeung Song <treeze.taeung@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1454577913-16401-3-git-send-email-treeze.taeung@gmail.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 67f43c00

tools/perf/Documentation/perf-config.txt

+67 −0
Original line number Diff line number Diff line
@@ -302,6 +302,73 @@ ui.*:: 
		in 'report' and 'top'. If this option is false, they are hidden.

		This option is only applied to TUI.



call-graph.*::

	When sub-commands 'top' and 'report' work with -g/—-children

	there're options in control of call-graph.



	call-graph.record-mode::

		The record-mode can be 'fp' (frame pointer), 'dwarf' and 'lbr'.

		The value of 'dwarf' is effective only if perf detect needed library

		(libunwind or a recent version of libdw).

		'lbr' only work for cpus that support it.



	call-graph.dump-size::

		The size of stack to dump in order to do post-unwinding. Default is 8192 (byte).

		When using dwarf into record-mode, the default size will be used if omitted.



	call-graph.print-type::

		The print-types can be graph (graph absolute), fractal (graph relative),

		flat and folded. This option controls a way to show overhead for each callchain

		entry. Suppose a following example.



                Overhead  Symbols

                ........  .......

                  40.00%  foo

                          |

                          ---foo

                             |

                             |--50.00%--bar

                             |          main

                             |

                              --50.00%--baz

                                        main



		This output is a 'fractal' format. The 'foo' came from 'bar' and 'baz' exactly

		half and half so 'fractal' shows 50.00% for each

		(meaning that it assumes 100% total overhead of 'foo').



		The 'graph' uses absolute overhead value of 'foo' as total so each of

		'bar' and 'baz' callchain will have 20.00% of overhead.

		If 'flat' is used, single column and linear exposure of call chains.

		'folded' mean call chains are displayed in a line, separated by semicolons.



	call-graph.order::

		This option controls print order of callchains. The default is

		'callee' which means callee is printed at top and then followed by its

		caller and so on. The 'caller' prints it in reverse order.



		If this option is not set and report.children or top.children is

		set to true (or the equivalent command line option is given),

		the default value of this option is changed to 'caller' for the

		execution of 'perf report' or 'perf top'. Other commands will

		still default to 'callee'.



	call-graph.sort-key::

		The callchains are merged if they contain same information.

		The sort-key option determines a way to compare the callchains.

		A value of 'sort-key' can be 'function' or 'address'.

		The default is 'function'.



	call-graph.threshold::

		When there're many callchains it'd print tons of lines. So perf omits

		small callchains under a certain overhead (threshold) and this option

		control the threshold. Default is 0.5 (%). The overhead is calculated

		by value depends on call-graph.print-type.



	call-graph.print-limit::

		This is a maximum number of lines of callchain printed for a single

		histogram entry. Default is 0 which means no limitation.



SEE ALSO

--------

linkperf:perf[1]